1. To share wisdom and knowledge with those who are younger: "He was eldering or presenting wisdom to younger members of the organization."
2. Greater than another person in age or seniority; or born before another person; especially, within a family, or having more seniority: "His sister is two years his elder."
3. One of the governing officers of a church, often having pastoral or teaching functions.

Factors to be considered when using the term elder

• The adjective elder is not a synonym for elderly.
• When comparisons are made between two people, elder means "older" but not necessarily "old": "Her elder brother is fourteen."
• The term eldest is used when three or more people are compared: "She is the eldest of four children."
• If age alone is to be expressed, one should use older or elderly instead of elder: "They made a survey of older citizens and his brother is still working as an elderly waiter."
• Unlike elder and its related forms, the adjectives old, older, and oldest can also be applied to things as well as to people.

If the share, or proportion, of people over a certain age is increasing, the population is considered to be aging.

Demographers use this type of measuring the population to determine if more people are getting older in addition to using median age as a factor.